Condensed Financial Information of Registrant (Schedule Of Condensed Financial Information Of Registrant, Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investments [Abstract]
Fixed maturity securities (amortized cost $4,394,983; $4,226,790)	$ 4,319,336	$ 4,088,311
Equity securities (cost $17,227; $35,041)	730,693	699,552
Short-term investments (cost $571; $27,057)	178,491	122,937
Total investments	5,228,520	4,910,800
Cash	550,903	289,776
Accrued investment income	59,128	52,474
Current income taxes	4,081	55,136
Deferred income taxes	33,013	42,903
Other assets	57,915	49,628
Total assets	7,103,397	6,514,188
Liabilities
Notes payable	573,729	398,330
Other liabilities	270,711	289,568
Total liabilities	5,555,252	4,992,057
Commitments and contingencies
Shareholders’ equity:
Common stock	98,947	98,947
Retained earnings	1,449,198	1,423,184
Total shareholders’ equity	1,548,145	1,522,131	$ 2,140,281
Total liabilities and shareholders’ equity	7,103,397	6,514,188
Amortized cost on fixed maturities trading investments	4,394,983	4,226,790
Cost - equity security trading investments	654,939	668,843
Cost - short-term investments	179,375	123,928
Parent Company
Investments [Abstract]
Fixed maturity securities (amortized cost $4,394,983; $4,226,790)	9,949	10,907
Equity securities (cost $17,227; $35,041)	28,027	51,416
Short-term investments (cost $571; $27,057)	571	27,059
Investment in subsidiaries	2,084,346	1,833,372
Total investments	2,122,893	1,922,754
Cash	4,698	6,218
Accrued investment income	141	149
Current income taxes	5,148	55,777
Deferred income taxes	1,544	1,072
Other assets	1,499	1,493
Total assets	2,151,587	2,000,844
Liabilities
Other liabilities	5,751	5,214
Total liabilities	603,442	478,713
Commitments and contingencies
Shareholders’ equity:
Common stock	98,947	98,947
Retained earnings	1,449,198	1,423,184
Total shareholders’ equity	1,548,145	1,522,131
Total liabilities and shareholders’ equity	2,151,587	2,000,844
Amortized cost on fixed maturities trading investments	9,979	10,908
Cost - equity security trading investments	17,227	35,041
Cost - short-term investments	571	27,057
Parent Company | Affiliated Entity
Investments [Abstract]
Amounts receivable	503	516
Income tax receivable	15,161	12,865
Liabilities
Notes payable	2,753	90
Income tax payable	21,209	75,079
Parent Company | Nonrelated Party
Liabilities
Notes payable	$ 573,729	$ 398,330